Clamp buckle



pril 16, 1940.

1 A. BARETT 2,197,535

CLAMP BUCKLE Filed Aug. 17, 1938 Patented Apr. 16, 1940 UNITED STATES PATENT OFFICE 1 Claim.

The present invention pertains generally to buckles, more particularly to friction grip buckles, and specifically to friction grip buckles of the locking lever type, especially adapted for the interconnecting of the ends of waist belts, straps of shoes and of sportwear and the like, and for a, variety of analogous purposes, without necessitating the puncturing of the belt, strap or the like at various points, as would have to be done were the conventional type of tongued buckle employed: such a friction grip buckle may aptly be termed a clamp buckle.

As is well known to those skilled in the art, friction grip buckles of this type, for successful use, are generally limited to belts of uniform and specified thicknesses, i. e., a given clamp buckle is most successfully usable with a strap. of a specific thickness; and a strap, substantially greater or less in thickness than the strap of the specific thickness, is not usable with the given clamp buckle. This limitation upon the use of clamp buckles is due to the fact that they are ordinarily constructed to accommodate a specific thickness of material, and any substantial deviation in thickness from the selected specific thickness of material either permits the material to slip Within the clamp buckle, or renders impossible the insertion and the engagement of the material in the clamp buckle.

The primary object of my invention is to provide an improved clamp buckle of the locking lever type which will accommodate, and adapt itself for use with, materials of substantially differing thickness.

Another object of my invention is to provide an improved clamp buckle of the character described Which is remarkably simple in construction and inexpensive to manufacture.

The attainment of these and other objects of my invention and the advantages attendant upon its use will become apparent, especially to those skilled in the art, from a consideration of the i following description, together with the accompanying drawing, which forms a part of the specification, wherein:

Figs. l, 2 and 3 represent an underside plan View, a side elevation, and an end view, respectively, of the plate or shell of the improved clamp buckle.

Figs. 4, 5 and 6 represent an underside plan view, a side elevation, and an end view, respectively, of the locking lever of the improved clamp buckle.

Fig. 7 is an underside view of the assembled improved clamp buckle, with one end of a strap connected to the locking lever, and a portion of a strap engaged between the plate and the locking lever of the improved clamp buckle.

Fig. 8 is a side elevation in section along the line 8, 3 of Fig. 7, showing the engagement of a portion of a strap between the plate and the locking lever of the improved clamp buckle.

Fig. 9 is an end view, seen from the right, of the assembled improved clamp buckle shown in Figs. 7 and 8.

Fig. 10 is another end view, seen from the right, of the assembled improved clamp buckle shown in Figs. 7 and 8, but in this view, the portion of a strap engaged between the plate and the lockinlever of the improved clamp buckle is substantially thicker than the corresponding portion of a strap shown in Figs. 8 and 9.

Figs. v11 and l2 represent an underside plan View and an end view, respectively, of a modification of the locking lever of the improved clamp buckle.

Fig. 13 is an end view of an assembled improved clamp buckle, provided with the locking lever shown in Figs. 11 and l2, showing the engagement of a portion of a strap of oversize thickness between the plate and the locking lever of this modication of the improved clamp buckle.

Inthe drawing, I is the plate or shell of the improved clamp buckle, having inner and outer facescurved in the manners shown, and having the sides 2 mutually parallel and substantially perpendicular to the plane of the plate I.l Extensions of portions of the sides 2 from the lugs 3, which are provided with the holes 4 for the rereption of the pivot pins of the locking lever. The locking lever 5, in thickness somewhat less than the thickness of the plate I, comprises an end portion 6, provided with a slot 'I to receive a strap 8, which either may be looped and fastened to itself lin the manner shown in Fig. 8, or may be fastened to the locking lever 5 by eyelets passing through the strap and the holes 3 in the midde portion of the locking lever, a middle portion IIJ, provided with the holes 9 and the pivot pins Il, receivable in the holes 4 in the lugs 3 of the plate i, and a locking portion I2, angularly disposed to the middle portion I0 and provided with a slot I3 extending into the middle portion Ill, as shown in Fig. 4 and Fig, '7, dividing the locking portion I2 into two friction members I4, I4. Particular attention should be given to the curvatures of the outer edges of the two friction members I4, I4 of the locking portion I2 of the locking lever 5, inasmuch as they are greater than is the curvature of the inner face of the plate l in the intersection of the plane of the friction members I Il, I I with the inner face of the plate I, so that the distance between the inner face of the plate l and the outer edges of the friction members Id, Ill at the point I5 is slightly less than is the distance between the inner face of the plate I and the outer edges of the friction members I4, Id at the points I 6, IS.

When now a strap I'I, in thickness slightly greater than the distance between the inner face of the plate I and the outer edges of the friction members I 4, I 4 at the point I5, is inserted into the opened improved clamp buckle, and the locking lever 5 is manipulated to close the improved clamp buckle, the strap I'l becomes engaged between the inner face of the plate I and the outer edges of the friction members Ill, I4, with stress exerted upon the strap Il, in amount somewhat greater near the center of its width than at its edges. Such engagement is shown in Fig.` 9. If

now this strap I'I is removed from the improved clamp buckle, and a strap I8, in thickness somewhat greater than the strap Il, is inserted into the opened improved clamp buckle, and the locking lever 5 is manipulated to close the improved clamp buckle, the greater thickness, or rather the too-great thickness, of the strap I8 causes the middle portion Ill of the locking lever 5 to yield slightly and to become bent outwardly to a very slight extent, as is shown in Fig. 10 at I9; and the bend in the middle portion Ill of the locking lever 5 manifests itself by the development of a line of bending starting at the end of the slot I 3 and extending longitudinally with respect to the improved clamp buckle. The strap I8 is now engaged between the inner face of the plate I and the outer edges of the friction members I 4, I Lwith stress exerted upon the strap I8, in amount substantially uniformly distributed along the outer edges of the friction members Ill, I4. The range of thicknesses of straps accommodatable by the improved Clamp buckle is substantially proporv tional to the difference in the distances between the inner face of the plate I and the outer edges of the friction members I 4, ill at the points I5 and I6, I6, respectively.

This adaptability of the improved clamp buckle to the thickness of the strap inserted therein, attained by the slight deformation of the middle portion Ill and minute rotational displacements of the friction members I4, I4, of the locking lever 5, is made possible by the presence of the slot I3; and it will be noted in Figs. 9 and 10 that the deformation of the middle portion IEI of the locking lever 5 effects a transformation of the shape of that portion of the slot I3 in the locking portion I 2 of the locking lever 5 from a rectangle to a trapezium, with the shorter parallel side dened by the engaged strap I8. The width of the slot i3 in the locking portion I2 of the lock-.ing lever 5 and the length of its extension into the middle portion I0 of the locking lever 5 are determined by the range of thicknesses of straps to be accommodated by the improved clamp buckle and by the character of the material out of which the improved clamp buckle is constructed, but these details of construction will present no diiculties to those skilled in the art.

The realization of the objects and purposes of my invention can be attained in the use of straps of an even greater range of thicknesses by means of a modification in the locking portion of the locking lever of the improved clamp buckle, as is shown in Figs. l1 and l2. In this modification of my invention, two slots 20, 2D, extending into the middle portion 2| of the locking lever, divide the locking portion of the locking lever into three friction members, of which the middle friction member 22 is only indirectly subjected to stresses exerted on the pivot pins of the locking lever. If desired, this middle friction member 22 may be accorded a length extending slightly beyond the curve defined by the outer edges of the two outer friction members 23, 23, either by so forming lt initially, or by bending inwardly toward the plate of the improved clamp buckle the middle portion ZI of the locking lever with which the middle friction member 22 is integral. When a strap of oversize thickness is inserted into the improved clamp buckle provided with such a locking lever, that part of the middle portion ZI of the locking lever, with which the middle friction member 22 is integral, will become bent outwardly along a line extending transversely with respect to the improved clamp buckle, and, at the same time, the middle portion 2I of the locking lever will yield slightly and Will become bent outwardly to slight extents along lines extending longitudinally with respect to the improved clampbuckle and starting at the endsof the slots 20, 20, with the result that the shapes of those portions of the slots 20, 20 in the locking portion of the locking lever are transformed from trapeziums to trapezoids, as shown in Fig. 13.

Although the improved clamp buckles herein described and illustrated embody the preferred forms of my invention, yet my invention is susceptible of such further modifications as may be fairly comprised by the scope of the appended claim.

Having thus described my invention, I claim:

A clamp buckle comprising a plate provided with lugs adapted to receive the pivot pins of a locking lever and a locking lever having a middle portion provided with pivot pins, a locking portion angularly disposed to the middle portion, and a slot bifurcating the locking portion and extending into the middle portion of the locking lover, the transverse outer edges of the locking portion cf the locking lever having curvatures greater than the curvature of the inner face of the plate in the intersection of the plane of the locking portion of the locking lever with the inner face of the plate.

LOUIS A. BARETT. 

